inferential statistics

distribution curves, levels of significance and probability, type 1 and type 2 errors

what kind of distribution curve is this

what kind of distribution curve is this

normal distribution curve

what kind of skewed distribution is this

left skew/negative distribution

what kind of skewed distribution is this

right skew/positive distribution

what is the mode

the most frequent score

what is the median

the middle point in the data

what is the mean

adding all the data and dividing by how many scores there are

what does probability mean in psychology

the likelihood that the pattern in the data could be due to chance

by assessing the probability…

…we can determine the significance of the results

high significance

low probability

high probability

low significance

type 1 error

false positive

what hypothesis is rejected but correct in a type 1 error

null hypothesis

what hypothesis is rejected but correct in a type 2 error

directional hypothesis

type 1 error

false positive

type 2 error

false negative

what error happens when the probability is too strict

type 2 error

what error happens when the probability is too lenient

type 1 error

68% of participants

percentage of participants that are within 1 standard deviation of the mean

95% of participants

percentage of participants within 2 standard deviations of the mean

99.7% of participants

percentage of participants within 3 standard deviations of the mean

two requirements of parametric tests

normal distribution, interval data

what stats test is for unrelated data at a nominal level

chi squared

what stats test is for related data at a nominal level

binominal sign

what stats test is for unrelated data at an at least ordinal level

mann whitney u

what stats test is for related data at an at least ordinal level

wilcoxon signed

what stats test is for correlations

spearman’s rho

if the tests name has an R in it then the observed value must be…

greater than or equal to the critical level in order to be significant

if the tests name doesn’t have an R in it then the observered value must be...

less than or equal to the critical level in order to be significant